Do you need longer lifetime for parts and tools?

Do you need shorter manufacturing time?

The solution is LASER!

 

Our defect analyses of breakdowns of machine parts clearly show that in almost every case the initial deterioration in material properties – such as cracks, abbrasive wear, fatigue from repeated plastic deformation or repeated temperature alteration, cavitations from chemical dissolution etc. - appears on the surface first.

 

So the material properties on the surfaces have a greater infuence for the structure of the whole part then those inside the material have.

 

It is very likely that the reinforcement methods of surfices, enhancing their material properties, will gain priority over methods improving material properties both inside and outside the material, like volume heat treating or the manufacturing of the parts from great amount of more and more expensive matrials.

 

These days, one of the most modern method of surface hardening is the laser heat treatment.

With this laser hardening process we can make the useful lifetime of machine parts – for example active and passive elements, rolling, sliding, pressing, cutting etc.components - with great friction, pressure, fatigue explosure lasting longer.

 

Advantages of laser hardening

 

• applicable for all hardenable materials

• hardened track width from 5 mm up to 70 mm, depth of hardened layer app. 0.8 – 1.5 mm, depending on material

• low distortion through very selective, high energy input during extremely short time

• after grinding or machining is not necessary

• temperature measurement and accurate process regulation possible

• fully repeatability, hardening temperature on the work piece surface is adjustable within + / - 10 °C

• quality control during the process of hardening with data storage

• selective hardening ofwork piece surfaces lead to hard surface with tough core and unaffected areas in the immediate vicinity

• oxidation free hardening withoutannealing colors is possible by using protection gas

• low modification of surface roughness

 

About the laser technology in manufacturing of parts and tools in general

 

The main methods of material processing can be reproduced by using laser technogy.

But in practice it has only advantage to use laser technology when it comes about the need of extremely high power density and very short working time and very selective power deployment and the usual technology is not suitable or not effective enough.

Just imagine that it is possible to heat material within a couple of tenth of seconds or even in milliseconds from room temperature to melting point of metals. So it can be uncomparably useful when it comes to a special need for extremly high concentration of high power within extremely short time.

 

The principle of laser heat treatment

 

The Laser heat treatment process means that heating power is applied to the surface by a specially designed apparatus which comprises a laser source, connections and optics, a robotic arm and controlling elements, to produce, place and control high power energy to the working place. The goal of every kind of hardening of hardenable steels is to reach the necessary cooling speed to cool the heated steel down so fast that the martensitic material structure will form.

In normal way at the quenching process the cooling media makes the material cool down.

But in the case of laser hardening there is no quenching media applied other than the core material behind the heated outer layer itself and the cooling will be done actually by the mean of heat transfer into the core of the material.

Through this very fast and concentrated way of heating and cooling of the outer layer of the material, any distorsion and deformation of the working part can be fully avoided, so it is highly advisable to apply this Laser hardening process strictly to fully finshed parts.

 

It comes from the above mentioned that after the Laser hardening process there is no need for maching, after grinding or any usual finishing rather then removing a very thin –thickness of some micrones –layer by polishing if polished surface is needed forming because of minor oxidation during the process. This oxidation can be minimalised by the use of protective gas but cannot be totally eliminated.

 

The process of the laser hardening can be repeated many times on the same part with the remainig effect of the last process.

 

The process also can be reproduced be recorded parameters and every parameter during the process will be stored.

 

Heat treatment parameters:

 

- Max power is 5 kW

- Width of heat treated stripe 6-72 mm (can be adjusted from robot program)

- Depth of heat treated zone is 0.6-1.5 mm (depending on material and geometry)

- Hardness can be between 50-67 HRC, for tool steels typically over 60 HRC

 

Parameters for robotic welding:

 

- 5 kW of laser power is available, width of the stripe of molten material  is 2.5 mm,

- Welding speed is 4-10 mm/s,

- Possibility of the use of protecting gas

- Possibility of using of very hard welding material (63 HRC)

- Wide variety of welding materials available

  (aluminium, stainless steels, heat resistant steels, HSS, hot work - cold work steels etc. )

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Parameters for manual welding:

 

- Power of 500W, the biggest in Hungary

- Wide selection of welding materials available

 

Coating:

 

- Possibilities of coatings: Titanium-Carbide (TiC), Tungsten-Carbide (WC) and Stellite coatings

- Thickness: 0.03-0.2 mm